aquaculture

Paul Adler examines young lettuce seedlings which are grown for about 3 weeks in a separate hydroponic system before they are set in the “conveyor production system” to remove nutrients from the rainbow trout effluent. (Photo by Keith Weller, USDA-ARS).

Adler, P.R. 1998. Phytoremediation of aquaculture effluents. Aquaponics J. 4(4):10-15. From the abstract:

The study is on an integrated system for rainbow trout production, effluent treatment and production of lettuce. The objective was to reuse water by removal of the nutrients in a vegetable product. The microscreen filter removes about 80% of the P excreted by the fish with the biosolids, leaving about 20% of the P in the effluent. A mass balance of system nutrients was conducted and it was determined that it takes 7.5 – 10 heads of lettuce to remove the P excreted in the effluent by the production of 1 pound of trout or 13 – 18 lettuce heads for each kg of feed consumed. Greenhouse studies demonstrated that by using the conveyor production strategy (CPS), phosphorus could be removed to <0.01 mg/L by lettuce without an apparent reduction in production or quality.

Conventional thinking regarding the use of food crops to clean aquaculture effluents has been that plants cannot remove nutrients in water to low levels without a reduction in productivity and quality. If water is distributed in a horizontal plug-flow pattern, all nutrients will be luxury consumed at the inlet, making nutrients limiting at the outlet and significant greenhouse space will be dedicated to growing plants that have no market value.

Because greenhouse space is expensive, productivity is critical for a profitable operation. A unique production system for lettuce, called the conveyor production strategy (CPS), was developed using thin-film technology for plant production in dilute aquaculture effluents. With the CPS, young plants are positioned near the solution inlet and are moved progressively, like along a conveyor belt, towards the outlet as they grow. Luxury consumption by lettuce (Lactuca sativa L.cv. Ostinata) enabled them to store P in their tissues early in their growth cycle for use later as water P levels decreased and influx could no longer meet current demands.

According to a speech presented at Aquavision 2002, the profile of the salmon industry in Chile is extensive:

• Modern salmon aquaculture first appeared in Chile around 1980 and has been developed in the southern Regions.

• Today, aquaculture is Chile’s fourth largest exporter, making Chile the world’s leading trout farming country and world number two in salmon farming. In 2001, the Chilean salmon industry exports were worth close to US $964 millions.

• Chile offers optimal environmental conditions: the temperature of the water, the quality of the water, geography, availability of fishmeal, and availability of suitable production sites.

• Aquaculture has a huge potential for development in Chile and investigations are progressing with several new species.

• The success of salmon farming has led to a number of social and economic effects. The southern regions now have some of the highest levels of employment in the country; currently 40,000 direct and indirect jobs result from the industry. These developments have also led to cultural changes as aquaculture requires trained people, at all levels.

The School of Aquaculture of the Catholic University of Temuco has hatchery and fish farming facilities, and offers aquaculture technician and degree courses. The web site offers content in spanish and english.

The FAO has published a profile of fisheries in Chile, (2000) which includes aquaculture. The FOA observe:

In Chile, this sector has been characterized for being one with bigger dynamics and importance of the national fishing sector, and for having reached a high development which began in the 80’s, mainly based in the culture of salmonoids and, at a lower level, molluscs, clams and seaweeds.

APFIC have published a number of reports available as free downloads about the rehabilitation of fisheries and aquaculture in coastal communities in those countries affected by the 1994 tsunami.

Strategic framework – Rehabilitation of fisheries and aquaculture in tsunami affected countries represents a regional strategic framework that has been developed in support of recovery and rehabilitation efforts following the earthquake and subsequent tsunami waves that originated off the west coast of northern Sumatra on the 26 December 2004 and that caused extensive damage to coastal communities in the region.

The framework presented consists of a vision for the rehabilitation of the fishery and aquaculture sectors which reflects an “ideal state” towards which all strategies and activities contribute and which avoids the mistakes of the past.

In response to the disaster, a consortium (CONSRN) of key regional agencies was formed with the objective of supporting coordination and harmonization of rehabilitation efforts in fisheries and aquaculture. In particular, it was agreed that activities were to focus on collating and disseminating information, carrying out assessments and supporting partners and governments to build a common vision for post-tsunami rehabilitation of the sector.

Other documents available as free downloads include: the report of the FAO/MOAC Joint tsunami assessment mission – Thailand. This is a report of a joint FAO/Ministry of Agriculture and Cooperatives (MOAC) detailed technical damage and needs assessment mission in the fisheries and agriculture sectors.

This is the final report of the Regional Workshop on Rehabilitation of Fisheries and Aquaculture in Coastal Communities of Tsunami Affected Countries in Asia held in Bangkok, Thailand from 28 February to 1 March 2005 is also available as a free download. Major topics discussed were: introduction to workshop and regional strategic framework; country priorities for rehabilitation; the rehabilitation vision and guiding principles; rehabilitation strategies; aligning donors/agencies/ countries to strategies and the workshop recommendations.

APFIC (The Asia-Pacific Fishery Commission) established by the Food and Agriculture Organization of the United Nations publish a range of research documents, including research into Myanmar aquaculture and inland fisheries (note: 6.84 MB) available as a free download.

This report is the outcome of two concurrent missions, one to coastal areas and one to inland areas, fielded by FAO-RAP, the Network of Aquaculture Centres in Asia-Pacific (NACA) and the Australian Centre for International Agricultural Research (ACIAR). The purpose was to review the status of aquaculture and small-scale inland fisheries, identify areas for technical assistance related to sustainable development of coastal and inland aquaculture and management of aquatic resources, and identify immediate assistance opportunities. The report includes the findings of the missions as well as conclusions and recommendations in support of the long term sustainability of fishery resources in Myanmar.

Fish and fish products are crucial in the nutrition and livelihoods of the Myanmar people. Whilst it is certainly recognized that fish is second only to rice in the diet of Myanmarians, little information is available on their patterns of consumption, inter-regional differences, availability and types of fish consumed. In this respect Myanmar is similar to many south-east Asian countries where emphasis is paid to rice production as a crucial element of food security, with little or no recognition of the fish component, which gives the rice-based diet much of its nutritional value outside of calories and crude protein.

Myanmar has impressive freshwater capture fisheries. The aquatic resource area of the river systems within Myanmar encompass a total of 8.2 million ha of permanent and seasonal water bodies. There were 29000 ha of freshwater fishponds and a further 40716 ha of shrimp ponds in 2001. These resources support, in many ways, the livelihoods of the people of Myanmar. Myanmar has a long coastline of nearly 3000 km and coastal aquaculture contributes significant export earnings and shows potential for future development and diversification. Of the total aquaculture production, an estimated 18794 tonnes comes from coastal aquaculture. Shrimp farming in particular has grown significantly in the past ten years, and small amounts of marine fish and crabs are also produced.

The FAO have also published this 1997 report on Support to Special Plan for Prawn and Shrimp Farming which gives some interesting insights into backyard scale shrimp hatcheries in Myanmar.

Neither intensive nor semi-intensive culture of shrimps has developed in Myanmar. Farming of marine shrimps has spread rapidly in South-east and South Asia, with exception of a few countries, including Myanmar. Myanmar’s neighbors Bangladesh to the north and Thailand to the south are both major producers of cultured marine shrimps. Culture of marine shrimps is now spreading rapidly in India. In all these countries export of cultured marine shrimps is a major earner of foreign exchange. There are about 30,00 acres (12,000 hectares) of traditional shrimp farms in operation which are mainly located in Rakhine State which borders with Bangladesh. The yield from the ponds are very low – 100 kgs/ha/year.

Lake Victoria is shared by Kenya, Tanzania and Uganda. It was named after the Queen of England and is the world’s largest tropical lake and the second largest freshwater lake. Since 1858, when the British explorer John Speke ‘discovered’ Lake Victoria, there has been a great deal of research undertaken on the lake, its inhabitants, the ecosystems and surrounding environments.

Nancy Chege, of the Worldwatch Institute, writes in www.cichlid-forum.com, Lake Victoria: a sick giant.

The ecological health of Lake Victoria has been affected profoundly as a result of a rapidly growing population, clearance of natural vegetation along the shores, a booming fish-export industry, the disappearance of several fish species native to the lake, prolific growth of algae, and dumping of untreated effluent by several industries. Much of the damage is vast and irreversible. Traditional lifestyles of lakeshore communities have been disrupted and are crumbling. There is a consensus among scientists that if an accelerated push to save the lake is not made soon, this much-needed body of water will cease to sustain life.

Lake Victoria represents a large scale issue to be resolved by governmental and business interests. Some cross-border responsibility is called for, rather than the pursuit of money with scant consideration for the health and welfare of the local communities whose livestyles and health depend on the health of the lake According to a Greenpeace report, “In the 1960s, for instance, the Nile perch was introduced into Lake Victoria in Africa and, within a decade, the local population of over 400 different smaller fish species declined from 80% to 2% of the lake’s total fish stocks. Probably 50% of the native species disappeared from Lake Victoria because they were not able to cope with the new invader exhibiting its insatiable hunger.”

At its fifth session, the Sub-Committee for the Development and Management of the Fisheries of Lake Victoria reviewed a variety of action programmes and made recommendations to Member Governments on their implementation. Programmes reviewed were concerned with fisheries development, management measures, protection of the environment and prevention of pollution, the water hyacinth, development of aquaculture, fish processing and marketing and technical, scientific and socio-economic issues involved in research policy. It was agreed by members that the concept of the International Code of Conduct for Responsible Fishing was applicable to Lake Victoria. The sub-committee agreed on procedures for the establishment of the Lake Victoria Fisheries Organization. The report is available online.

Chenge, again reports:

A more recent threat to the lake is the water hyacinth. With the deceptive appearance of a lush, green carpet, the hyacinth is a merciless, free-floating weed, reproducing rapidly and covering any uncovered territory. First noticed in 1989, the weed has already spread like wildfire, and has covered areas in all three countries. It forms a dense mat, blocking sunlight for organisms below, depleting the low concentrations of oxygen and trapping fishing boats and nets of all sizes. The hyacinth is an ideal habitat for snails that cause bilharzia and for snakes. Scientists are desperately trying to control the weed: their most promising approach involves harvesting the hyacinth and using it either for compost or for biogas production.

Richard O. Abila, Researcher, Kenya Marine and Fisheries Research Institute, Kisumu, Kenya; writes in Fish Trade and Food Security: Are They Reconcilable in Lake Victoria?:

The Lake Victoria fishery has come under increasing pressure in the last two decades. Fish production peaked in the early 1990s and currently catches of most species are showing downward trends. Despite this, there is greater demand for fish of Lake Victoria, chiefly Nile perch (Lates niloticus) and ‘dagaa’ (Rastrineobola argentea), in the export market and for fishmeal respectively, as well as for domestic consumption. The present situation is the consequence of the tremendous commercial transformation that the fishery of Lake Victoria has undergone in those 20 years. From a local-based subsistence fishery before 1980, it is presently dominated by fish processing factories funded from international sources, which aim at enhancing fish exports from East Africa to the developed world, so as to earn more foreign exchange. This takes place against a backdrop of a protein-starved local community whose livelihood depends on the lake. In the past, international trade on fisheries was taken for granted as the means to tackle poverty and food insecurity for fisheries-dependent communities. That idea has, however, been challenged in the last few years as researches look critically at the benefits of global fish trade vis-à-vis the costs, particularly in relation to food insecurity and environmental implications. This report is a further contribution to this debate. It tries to establish a link between the increased liberalization of trade in the fisheries of Lake Victoria and the food insecurity indicators. The paper is based on primary and secondary data collected at various times, published and unpublished documents as well as the author’s own observations over several years working as a researcher on socio-economic aspects of the Lake Victoria fishery. Because of the large investment already made in industrial fish processing, it would be in order to allow some amount of exports to continue. However, the quantities of exportable fish must be limited to ensure sustainable fisheries and reconciliation with the food security needs. Recommendations are made in four broad directions to make Lake Victoria fisheries more relevant to the food security needs of the local population. They include specific policy interventions, interventions in fisheries management, steps to enhance fish supply and refocusing the fish marketing strategies. There is also need for more incisive studies on the fish industry and at household level to understand in greater depth how the various factors raised in this study relate to each other and the magnitude of their contribution to food insecurity.